a $3 columnar

picked this up at a weekend market for $3... but what is it? new spines are red... spines are very thin and needle sharp...kinda looks like a thin Trichocereus. somewhat like a thinner version of T.spachianus or huascha. i was thinking of using it as a grafting stock.

Correct spelling, but the species doesn't need a capital letter. It's Peniocereus serpentinus

A few years ago I was doing some work in a little town in central victoria. We were doing regeneration work and were buying plants off an old lady who lived in the bush out of town. One day I noticed a bunch of cacti in pots several meters high. I complemented her on the cactus but she 'hated the damned things' and tried eagerely to pass them on to me. I wasn't complaining. The plant I got was several stems over a metre tall. at the time i didn't know what it was and considered it quite ugly. I had never seen it flower before. So I chopped it up in to pieces and gave heaps away to friends, and kept a bunch for grafting stock.I tried using it to graft little offsets or rebutia, mammalaria and gymnocalycium. These were some of the first grafts I ever did and none of them turned out to well. I found the stock would offset and put all its energy into the offset rather than the scion. One of my friends had really good success using this as a stock for a gymnocalycium.As a plant they grow really quickly in victoria, even in colder wet areas. I've seen little plants triple in size over one growth season. Once they're a bit bigger they tend to fall over, i've seen them tied up against walls and fences which looks ok if you want to retain the columnar look. The flowers are amazing, really big white flowers, and they produce quite a lot of them too.

I live in central vic, and the only reason i know its such plant is because i have one, but myne doesnt seem to grow. Hopefully this growing season it will kick in.In Melbourne, i saw a plant alot thicker then Lewis's one there, and about 2m tall staked up against the fence, it looked good being columnar, but the natural habit for it is to topple over when it is top heavy.